Discovery Report Middle North Canadian Watershed, HUC 8 – 11100301 Blaine, Canadian, Dewey, Ellis, Harper, Major, Oklahoma, and Woodward Counties, Oklahoma October 2012 Project Area Community List Community Name CID Blaine County Communities Blaine County Unincorporated Areas 400011 Canton 400012 Geary 400381 Greenfield 400013 Longdale 400014 Watonga 400016 Canadian County Communities Canadian County Unincorporated Areas 400485 Calumet 400268 El Reno 405377 Mustang 400409 Union City 400334 Yukon 400028 Dewey County Communities Dewey County Unincorporated Areas 400626 Seiling 400058 Vici 400448 Ellis County Communities Ellis County Unincorporated Areas N/A Harper County Communities Harper County Unincorporated Areas 405449 Major County Communities Major County Unincorporated Areas 400110 Oklahoma County Communities 400466 Oklahoma County Unincorporated Areas 400466 Bethany 400254 Oklahoma City 405378 Warr Acres 400449 Woodlawn Park 400340 Tribes Cheyenne-Arapaho Tribes of Oklahoma 400590 Woodward County Communities Woodward County Unincorporated Areas 400500 Mooreland 400230 Mutual 405383 Sharon 400231 Woodward 400232 Middle North Canadian Discovery Report Table of Contents I. Discovery Overview ............................................................................................................................ 1 i. Watershed Selection ..................................................................................................................... 2 II. Discovery Efforts .............................................................................................................................. 15 i. Engagement Plan ........................................................................................................................ 15 ii. Pre-Discovery Efforts ................................................................................................................. 16 iii. Discovery Meeting ..................................................................................................................... 17 iv. Data Gathering Overview ........................................................................................................... 19 III. Watershed Findings ........................................................................................................................... 32 i. Engineering Review of Community Comments ......................................................................... 32 ii. Post-Discovery Hydrology ......................................................................................................... 32 iii. Frequency Analysis .................................................................................................................... 33 iv. Post-Discovery CNMS Analysis ................................................................................................ 33 v. Post- Discovery Hydraulics and Floodplain Analysis ................................................................ 48 IV. Watershed Options ............................................................................................................................ 49 Tables Table 1: Land Use within the Watershed ............................................................................................... 4 Table 2: Effective Flood Insurance Rate Map Dates .............................................................................. 5 Table 3: Stream Miles in the Watershed ................................................................................................ 6 Table 4: NVUE Approximate Stream Mileage in the Watershed .......................................................... 8 Table 5: Recent Major Disaster Declarations in the Watershed ............................................................. 8 Table 6: Mitigation Plan Status .............................................................................................................. 9 Table 7: NFIP Insurance Claims by County and Community in the Watershed .................................. 10 Table 8: Non-Mitigated Repetitive and Severe Repetitive Losses in the Watershed ........................... 11 Table 9: Watershed Risk Factor Rankings ........................................................................................... 12 Table 10: Project Team ........................................................................................................................ 15 Table 11: Project Discovery Meeting Time and Location ................................................................... 17 Table 12: Data Collection Summary - Pre-Discovery Meeting............................................................ 21 Table 13: Summary of Data Collected During the Discovery Meeting and Post-Meeting .................. 22 Table 14: Comparison of 1-Percent-Annual-Chance Peak Flows of Gage Frequency Analysis and Effective Discharges ............................................................................................................ 35 Table 15: CNMS Validation Status for Detailed Streams .................................................................... 36 Table 16: Failed Element for Streams .................................................................................................. 36 i Middle North Canadian Discovery Report Table 17: Hydrologic and Hydraulic Information for Enhanced Streams ............................................ 45 Table 18: Hydraulic Issues with Floodplain Boundaries ...................................................................... 49 Table 19: LOMRs that Revise Hydraulics within the Watershed ........................................................ 49 Table 20: Potential Watershed Needs and Actions .............................................................................. 51 Table 21: Metrics and Rankings of Needs............................................................................................ 54 Figures Figure 1: Watershed Locator Map .......................................................................................................... 3 Figure 2: 10- Year View of Urban Change within the Watershed ......................................................... 7 Figure 3: Risk Factors and Topographic Data Availability for the Watershed .................................... 12 Figure 4: USGS Gage Locations .......................................................................................................... 34 Appendices Appedix A: Discovery Map.................................................................................................................. 59 ii Middle North Canadian Discovery Report Acronyms and Abbreviations BFE Base Flood Elevation CAV Community Assistance Visit CEO Chief Executive Officer CERCLA Comprehensive Environmental Response, Compensation, and Liability Act CFS Cubic Feet per Second CID Community Identification number CLOMR Conditional Letter of Map Revision CNMS Coordinated Needs Management Strategy CRS Community Rating System DEM Digital Elevation Model eLOMA Electronic Letter of Map Amendment EPA Environmental Protection Agency ESRI Environmental Systems Research Institute FEMA Federal Emergency Management Agency FIRM Flood Insurance Rate Map FIS Flood Insurance Study FPA Floodplain Administrator FY Fiscal Year G&S Guidelines and Standards for Flood Hazard Mapping Partners GIS Geographic Information System HEC-1 Hydrologic Engineering Center – Hydrologic model program HEC-2 Hydrologic Engineering Center – Hydraulic model program HMP Hazard Mitigation Plan HUC Hydrologic Unit Code IDIQ Indefinite Delivery Indefinite Quantity LiDAR Light Detection and Ranging System LOMA Letter of Map Amendment LOMA-F Letter of Map Amendment based on Fill LOMC Letter of Map Change LOMR Letter of Map Revision MIP Mapping Information Platform MLI Midterm Levee Inventory MNC Middle North Canadian Watershed MXD ArcMap map document extension NAVD North American Vertical Datum NCDC National Climatic Data Center NFIP National Flood Insurance Program NHD National Hydrologic Dataset NRCS Natural Resources Conservation Service NVUE New Validated or Updated Engineering OKC Oklahoma City OWRB Oklahoma Water Resources Board PDF Portable Document Format file iii Middle North Canadian Discovery Report PMR Physical Map Revision RCRA Resource Conservation and Recovery Act RSC Regional Service Center Risk MAP Risk Mapping, Assessment, and Planning Program RL Repetitive Loss SFHA Special Flood Hazard Area SHMO State Hazard Mitigation Officer SHP ESRI Shapefile SQ MI Square Mile SRL Severe Repetitive Loss USACE U.S. Army Corps of Engineers USDA U.S. Department of Agriculture USGS U.S. Geological Survey iv Middle North Canadian Discovery Report I. Discovery Overview The Federal Emergency Management Agency (FEMA) is currently implementing the Risk Mapping, Assessment, and Planning (Risk MAP) Program across the Nation. The purpose of Risk MAP is the continued improvement of flood hazard information for the National Flood Insurance Program (NFIP); the promotion of increased national awareness and understanding of flood risk; and the support of Federal, State, and local mitigation actions necessary to reduce risk. The vision and intent of the Risk MAP Program is to, through collaboration with State and local entities, deliver quality data that increases public awareness and leads to mitigation actions that reduce risk to life and property. To achieve this vision, FEMA has transformed its traditional flood identification and mapping efforts into an integrated process